Tag: UDP

Review/Perspective: UDP Operations

1.1.f Explain UDP operations

  • 1.1.f [i] Starvation
  • 1.1.f [ii] Latency
  • 1.1.f [iii] RTP/RTCP concepts

 

Starvation

Starvation occurs primarily on TCP traffic when it is combined in the same class of service as UDP traffic.  If UDP traffic is the source of congestion, TCP traffic in the same class is essentially starved because of the way TCP behaves during times of congestion.  TCP will slow down the rate at which it transmits traffic when it experiences congestion…only exacerbating the problem even further.

 

UDP Latency

Outside from the typical causes of latency, UDP has the ability to be sent without acknowledgement, which sets it apart from TCP in that communications don’t have to wait for an acknowledgement before being sent.  Allowing UDP to be considered ‘faster’ than TCP in terms of transmitting data, lacking the reliability that TCP provides.

 

RTP/RTCP Concepts

RTP is an IETF standard protocol made to manage the real time streams of data as they’re sent.  RTP typically carries realtime media streams such as audio and video and is carried using UDP.

RTCP is an out of band control protocol encapsulated with RTP to monitor quality of service, provides transmission statistics, and aids in syncronization of multiple media streams.

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User Datagram Protocol (UDP)

UDP is a protocol that’s used when you either don’t need reliable transport, or can’t afford the costs of reliable traffic transport.  Reliable packet delivery can be slow, and some applications can’t wait to send subsequent packets if it’s waiting on an acknowledgement from the other end.  For example voice audio RTP packets must be sent immediately without waiting otherwise the audio that’s carried on those voice packets will arrive out of order or late and cause serious degraded voice quality problems.

UDP packets are considered connectionless and do not have as much information inside their headers making this type of traffic ideal for applications that are sensitive to packet loss or delay.

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